This FIRST application seeks support for a five-year, process-oriented study of stimulus control transfer in individuals with severe to moderate intellectual disabilities. The research will contribute to a general theoretical account of such transfer, and also to the development of a more effective and efficient teaching technology for this population. The project derives from recent studies that sought reliable methods for teaching arbitrary conditional relations (i.e., those not based on common physical features). Those studies made obvious certain questions about basic processes involved in stimulus control transfer. For example, in programs that teach by graduated stimulus change (i.e., stimulus control shaping), what kinds of relations among the stimuli result in successful transfer? What accounts for failure to transfer during these procedures? Answers to these questions would contribute not only to a theoretical account of stimulus control transfer, but to the prediction of optimal arrangements of training conditions. Regrettably, relevant research during the past two decades has not much clarified the basic processes involved; theoretical analyses in this area essentially stalled more than a decade ago. As a consequence, stimulus control shaping continues to be regarded as more empirically derived art than theoretically integrated science. My proposed project has two main goals. First, I plan to conduct a theoretically guided analysis of basic processes involved in stimulus control shaping. In particular, I will analyze interactions among feature classes (stimulus classes defined by physical features) in the course of stimulus control transfer. Second, I. plan to apply what I learn from this analysis to improve discrimination training methodology. My Specific Aims are to: (1) examine processes that may be involved in stimulus control transfer via gradual stimulus changes occurring within a single stimulus dimension. I will determine the extent to which subjects with mental retardation classify stimuli in a stimulus control shaping series as members of the same or different feature classes; (2) investigate how stimulus classification and measured mental age (MA) are related; (3) develop and evaluate the effectiveness of feature-class assessment procedures for improving sample stimulus control shaping methodology; (4) extend the feature-class analysis and programming methods to interdimensional stimulus control transfer; (5) evaluate the effectiveness of sample stimulus-control shaping methods for solving educationally relevant problems of individuals with developmental disabilities. In doing so, I plan to make use of newly available computer technology to make stimulus control shaping more easily accomplished in instructional settings; and (6) begin to consolidate the sample shaping assessment and teaching procedures into an automated, computer-managed instructional technology that is appropriate for wider applications in special education.